The molecular and genetic distances and relations between enzyme and ribosomal protein-controlling regions of pneumococcal DNA will be studied. The genes available in various arrays in this region include ribosome modifying streptomycin and erythromycin resistance markers, a gene controlling mannitol dehydrogenase, and several altering folic acid synthetase to produce sulfonamide resistance. A sulfonamide marker region can be present as a tandem duplication with various heterozygotic gene arrangements. All these genes are measured quantitatively by DNA transformation with intact DNA or its fractionated and rescued (hybridized) single strands. The gene activities are studied before and after pretreatment of the DNA in vitro with various degrees of mechanical shear, or after systematic degradation with nucleases of defined biochemical specificity for breaking the DNA molecules in one or two strands at the middles or at the 3' or 5' ends of strands. Physically fractionated or reisolated transforming DNA is also being studied to determine the molecular nature of early steps in transformation and recombination in the recipient cell. BIBLIOGRAPHIC REFERENCES: Rotheim, M.B., and Hotchkiss, R.D. (1975) Canad. J. Microb., 21:1139-1143. A modifier mutation affecting utilization of mannitol in pneumococcus: Ledbetter, M.L.S., and Hotchkiss, R.D. (1975) Genetics, 80:679-694. Recombination as a requirement for segregation of a partially diploid mutant of pneumococcus.